1. Field of the Invention
The present invention relates to a wind direction controlling apparatus provided at an air discharge port of an air conditioner of an automobile or the like. Particularly, the present invention relates to a wind direction controlling apparatus driven by a motor or a like drive device to automatically deflect the direction of wind from the air discharge port.
2. Description of the Related Art
FIGS. 4 through 11 show an example of a conventional wind direction controlling apparatus. Referring to these drawings, the apparatus includes a case 1 mounted on an air discharge port, not shown. As shown in FIGS. 5 and 6, a plurality of horizontal fins 2 are rotatably supported by rotary shafts 2a within the case 1 so as to deflect wind from the air discharge port in vertical directions (i.e., up and down). Pins 2b at the respective inward edge portions of the horizontal fins 2 are rotatably passed through a first joint 3 (comprising two joint members in the illustrated example) so that the horizontal fins 2 are pivotally joined to the first joint 3. A plurality of vertical fins 4 are swingably supported by rotary shafts 4a within the case 1 in such a manner as to be swingable about the rotary shafts 4a and thus be able to deflect wind from the air discharge port in horizontal directions (i.e., left and right). Dials 5 are provided integrally with some of the vertical fins 4 so as to manually operate the vertical fins 4. Pins 4b at the respective inward edge portions of the vertical fins 4 are rotatably passed through a second joint 6 (comprising two joint men, hers) so that the vertical fins 4 are pivotally joined to the second joint 6. The angle by which the vertical fins 4 can be operated is limited by the abutment of one of the ends of the second joint 6 on an inner side surface of the case 1. A machine room 7 is defined within the case 1 at a substantially central location thereof. A geared motor 8, serving as a drive device, is elastically accommodated in the machine room 7 through a cushioning material 9. As shown in FIGS. 7 and 9, the geared motor 8 has an output shaft 10, to which a drive roller 11 is fixed. As shown in FIGS. 5 and 8, a rod 12 has an elongated hole portion 12a formed at a substantially central position thereof and kept in link-engagement with an eccentric pin 11a of the drive roller 11. Since the wind direction controlling apparatus has structures of substantially the same construction on either side of the machine room 7, only one of the structures will be described.
As best shown in FIG. 6, the rod 12 is disposed in such a manner as to overlap with and engage with a hook-shaped engagement portion 6a at an inward edge portion of the second joint 6 below the rod 12. A plate spring 13 is bent into a shape having a substantially U-shaped cross-section, and a cap 14 is fitted on an end portion of the plate spring 13. The plate spring 13 has a resilience by virtue of which the spring 13 exerts a clamping force, which force is transmitted through the cap 14 to the rod 12. Thus, a clutch is formed between the rod 12 and the second joint 6, providing the function of frictional engagement.
The operation of the conventional wind direction controlling apparatus will be described.
When the geared motor 8 is energized, the output shaft 10 and the drive roller 11 fixed to it are rotated. As the drive roller 11 rotates in the direction X shown in FIG. 4, the rod 12, in link-engagement with the eccentric pin 11a, reciprocates linearly in the directions Y shown in FIG. 4. The linear reciprocation of the rod 12 causes, through the caps 14 and the plate springs 13, the second joint 6 to swing back and forth, which in turn causes the vertical fins 4 to swing in the directions indicated by the arrows R in FIG. 4. Consequently, wind from the air discharge port is automatically deflected continuously in horizontal directions to blow in the associated space. For instance, the deflected wind blows in the interior of an automobile toward the driver's and assistant's seats.
When the geared motor 8 is at rest, the vertical fins 4 can be oriented in a desired horizontal orientation within a certain range by suitably operating the associated dial 5, thereby causing the friction clutch section, comprising the cap 14 and the plate spring 13, and the joint member 6 to slide on the rod 12 until the desired orientation is achieved. The horizontal fins 2 can be manually oriented in a desired vertical orientation within a certain range.
The conventional wind direction controlling apparatus having the above-described construction entails the following problem. When the vertical fins 4 are oriented to the maximum extent, for example, oriented to the right extreme, as shown FIG. 8, at the time point at which the end of the joint member 6 abuts on an inner side surface of the case 1 (with the position of the eccentric pin 11a of the drive roller 11 corresponding to that shown in FIG. 10(a)-(ii)), force A of a magnitude corresponding to that of the frictional force of the friction clutch section acts on the geared motor 8. Since the geared motor 8 is elastically accommodated in the machine room 7 through the cushioning material 9, the geared motor 8 is tilted in the direction B shown in FIG. 9.
At such times, the load on the geared motor 8 causes periodical increases in the level of noise generated by the reduction gear of the motor 8 (the noise will hereinafter be referred to as "the gear noise"), as shown in FIG. 10(b), and the gear noise can be very discomforting.
In order to eliminate the above problem, the frictional force of the friction clutch section may be reduced. However, if, for this purpose, the thickness of the rod 12 is reduced simply over the entire range thereof, so as to reduce the amount by which the U-shaped plate spring 13 is deflected in the direction in which it is opened, the rigidity of the rod 12 may decrease, particularly at high temperatures, and the rod 12 may be deformed to cause operational failure.
The above problem may be eliminated by adopting the construction shown in FIGS. 11(a) and 11(b). Here, a rod 15 has a recess 15c formed therein, the recess 15c normally engaging with a projection 16a of a cap 16. The friction clutch of the construction is positioned in such a manner that the end of the joint 6 is kept at a neutral position at which the joint 6 does not abut on an inner surface of the case 1 even when the vertical fins 4 are at a reversal point of their swinging during the operation of the geared motor 8. With this arrangement, it is possible to reduce variations in the load on the geared motor 8 which can be caused at the time of reversal of the vertical fins 4. However, in a manual operation for adjusting the orientation of the vertical fins 4, it is necessary to cause the projection 16a of the cap 16 to clear the recess 15c of the rod 15, as shown in FIG. 11(b). This is disadvantageous in that a relatively great force is inevitably applied before the clearing action, and, thereafter, the resultant reaction may cause a great change in the angle of orientation of the vertical fins 4. Thus, it is difficult to perform fine adjustment of orientation; besides, the force required for the operation changes before and after the clearing action, thereby failing to provide good operability.